The present invention relates to protocol testing, and more particularly to a method of configuring a filter for a data stream organized in frames in a protocol tester.
Protocol testers record a large amount of data. Therefore for a meaningful evaluation the amount of data to be shown an operator on a monitor is reduced by various types of filters. FIG. 1 shows a graphical user interface (GUI) of a display unit with several information windows and several icons by which selections may be made and functions triggered, as known from Windows® application programs. Predefined filter groups are shown in a group window 10 with the associated filters shown in a filter window 12. The selection of the filter type with which a data stream between a data source 16 and a data sink 18 is filtered is shown for clarification in a graphic window 14. The data source 16 may have several individual data sources, the initial data of the individual data sources being compiled into a serial data stream that then passes through the selected filter. For the sake of clarity only the features of the filter configuration known from the prior art which are relevant for understanding the current invention are explained in more detail below.
By clicking on an appropriate icon 20 the display changes from FIG. 1 to FIG. 2. A stack window 22 shows various configured protocol stacks, with a scroll bar 24 allowing additional configured protocol stacks to be shown in this window. A protocol window 26 shows the protocols belonging to the protocol stack highlighted in the first window 22. A message window 28 shows messages belonging to the protocol stack highlighted in the protocol window 26. A parameter window 30 shows the parameters or field names belonging to the message highlighted in the message window 28. By clicking on the appropriate icon 32 the corresponding filter is enabled and the display changes to that shown in FIG. 3.
As is seen from the graphic window 14 in FIG. 3 the data stream now runs through the filter. In the present example the task of an operator is to extract from the data stream frames containing an RPAC-UL message. Therefore the operator has to configure the filter accordingly. This requires considerable expert knowledge. First the operator has to know which protocol contains the RPAC-UL message and, second, in which protocol stack the relevant protocol is to be found. A skilled user may have a good idea where to look, but an unskilled user has to take a chance or systematically test all protocol stacks and protocols until the corresponding RPAC-UL message is shown in a window. With luck, expertise or patience the user eventually receives the display shown in FIG. 4 where the RPAC-UL message appears in the message window 28 as part of the SMRP protocol (protocol window 26) which is part of the protocol stack umts_iu_cs_ps_sms_i . . . (stack window 22). By highlighting RPAC-UL (FIG. 5) the filter is configured accordingly and the data stream emanating from the data source 16 is filtered accordingly.
The result of the filtering is shown in FIG. 6 where the frames from the data stream containing the RPAC-UL message are shown in a short view window 36. The short view window 36 has several columns: consecutive numbers of the frames 39; time stamps assigned to the frames 40; data source 42; and in an ordered fashion the protocols and associated messages contained in the relevant frame 44a, 44b, 46a, 46b, 48a, 48b. As shown, frame number 681 is highlighted. The content of the highlighted frame, sorted by protocols, is shown in a fully decoded format in a frame view window 38. Also in the short view window 36 a second protocol SCCOP is further highlighted 50. In the frame view window 38 the selected frame 52 is shown starting with the protocol SCCOP 54. A first column 56 shows a bitmask, a second column 58 shows the name of a protocol data unit and a third column 60 shows a corresponding comment or value belonging thereto. In a first section 62 the protocol data units of message SD are shown. In a selected frame window 64 the selected frame is shown in a hexadecimal format. As shown in the short view window 36 five frames have been selected by filtering the data stream. FIG. 7 shows in a configuration window 66 relevant data for the configuration of the filter for displaying the result shown in FIG. 6. This information may be saved and offered later for selection by the operator as a predefined filter.
What is desired is a method of configuring a filter in a simple manner without requiring extensive expert knowledge on the part of a user.